1. Field of the Invention
The present general inventive concept relates to an inkjet print head and a method of manufacturing the same, and more particularly, to an inkjet print head mounted on an inkjet printer to eject ink in fine droplets and a method of manufacturing the same.
2. Description of the Related Art
A conventional inkjet print head ejects fine droplets of ink onto a surface of a recording medium through a nozzle to obtain a desired image. The inkjet print head is generally classified, depending on a pressure generating element, as a thermal head type for generating bubbles using heat applied to the ink through an electro-thermal transducer or a piezoelectric head type for generating bubbles in the ink using pressure applied to the ink through an electro-mechanical transducer.
Regarding the thermal head type, current is applied to a heat resistor to heat the ink to a temperature of hundreds of degrees in order to boil the ink, thereby generating the bubbles. As the bubbles expand, the ink that is temporarily stored in an ink chamber is pressurized and is ejected through the nozzle.
A thermal inkjet print head typically has several hundreds of densely integrated nozzles in order to increase dots per inch (DPI).
The thermal inkjet print head is manufactured by forming a plurality of layers on a silicon substrate. Specifically, a logic region for controlling current supplied to the heat resistor used to operate the inkjet print head is formed on a wafer, and then an interlayer dielectric (ILD) layer, a metal interconnection layer, and an intermetal dielectric (IMD) layer are sequentially deposited on the logic region. Thereafter, an ink-feed hole and a nozzle are formed to extend through the layers, thereby completing the inkjet print head.
In this process, the interlayer dielectric layer should have a high degree of flatness since it is formed directly on the logic region. For this reason, conventional interlayer dielectric layers are generally made of boron phosphorus silicate glass (BPSG) having a high viscosity.
Since the BPSG has moisture absorption properties and the interlayer dielectric layer has an end that is typically exposed to the ink-feed hole to be in direct contact with the ink, the BPSG tends to absorb moisture from the ink. As a result, problems such as interface de-lamination, corrosion and electrical short-circuit of the metal interconnection layer and the heater, device malfunction in the logic region, etc., are generated. Such problems deteriorate characteristics of the inkjet print head and shorten its lifespan.